d4088803f5
There are several problems in lzo_compress_pages() preventing it from being subpage compatible: - No page offset is calculated when reading from inode pages For subpage case, we could have @start which is not aligned to PAGE_SIZE. Thus the destination where we read data from must take offset in page into consideration. - The padding for segment header is bound to PAGE_SIZE This means, for subpage case we can skip several corners where on x86 machines we need to add padding zeros. The rework will: - Update the comment to replace "page" with "sector" - Introduce a new helper, copy_compressed_data_to_page(), to do the copy So that we don't need to bother page switching for both input and output. Now in lzo_compress_pages() we only care about page switching for input, while in copy_compressed_data_to_page() we only care about the page switching for output. - Only one main cursor For lzo_compress_pages() we use @cur_in as main cursor. It will be the file offset we are currently at. All other helper variables will be only declared inside the loop. For copy_compressed_data_to_page() it's similar, we will have @cur_out at the main cursor, which records how many bytes are in the output. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.